Question: $-\dfrac{9}{10} + \dfrac{7}{2} = {?}$
Explanation: $ = - {\dfrac{9 \times 1}{10 \times 1}} + {\dfrac{7 \times 5}{2 \times 5}} $ $ = - {\dfrac{9}{10}} + {\dfrac{35}{10}} $ $ = - \dfrac{{9} + {35}}{10} $ $ = \dfrac{26}{10}$